1. Field of the Invention
The present invention relates to a telephone system which includes a plurality of extension telephone sets dedicated to handling terminating calls and is capable of automatic distribution of terminating calls to the respective extension telephone sets such that each extension telephone set handles substantially equal quantities of terminating calls and to a method of performing communication within the telephone system.
2. Description of Related Art
The telephone system of this type is, for example, an electronic private branch exchange capable of automatically distributing terminating calls to handle a plurality of extension telephone sets as dedicated terminals for receiving external terminating calls. Thus, the respective extension telephone sets dedicated to handling terminating calls can perform dedicated procedures for receiving, for example, reservations of airplane tickets, etc.
The dedicated extension telephone sets are handled as a group and terminating calls to the extension telephone set group are equally distributed to each telephone set. When none of the extension telephone sets is idle in the presence of terminating calls, a queue of terminating calls is formed, and the first terminating call of the queue is transferred to an extension telephone set as soon as the same becomes idle.
A management terminal is provided for managing the extension telephone set group to monitor the situation of the group, creating management data, etc.
The management terminal includes an application processor, a display, a keyboard input unit, a printer, etc. The application processor handles data on the function of automatically distributing terminating calls. For example, the application processor receives from a private branch exchange call data concerning terminating calls for the extension telephone set group, stores and compiles the call data. The processor responds to data inputted from the keyboard input unit by a supervisor (an operator which operates the management terminal) to calculate the number of terminating calls handled by a predetermined agent (an operator which operates an extension telephone set), the time required for telephonic communications, etc., and outputs the results on the printer and/or display. If a plurality of extension telephone set groups are beforehand set, the application processor can calculate the number of terminating calls and the time required for telephonic communication for each extension telephone set group and output the results on a printer or a display. It can also calculate the number of terminating calls and the time required for telephonic communications for each extension telephone set and output the result on the printer or the display.
In the terminating call automatic distributing function, the call data concerning the terminating call is compiled and managed for each agent, each extension telephone set group and each extension telephone set. Therefore, it is necessary to identify each agent, each extension telephone set group and each extension telephone set. To this end, an ID number is allocated to each agent, a pilot number is allocated to each extension telephone set group, and a logical number is allocated to each communication line which is dedicated to terminating calls and is led to the respective extension telephone sets of each group, thereby to enable identification of each agent, each extension telephone set group and each extension telephone set.
In performing terminating call processing procedures, an agent must first perform a log-in operation on an extension telephone set in the group to which the agent belongs and then declare the start of the procedure. The log-in operation includes pressing a log key provided at the telephone set and then dialing the agent's ID number. By these operations, the fact that the terminating call dedicated line of the extension telephone set corresponds to the ID number and that a terminating call can be handled by using the terminating call dedicated line is reported to the control system of the private branch exchange and to the application processor. There is an inverse operation called a log-out operation which includes disconnecting a terminating call dedicated line from the ID number and reporting the termination of the procedures to the control system of the private branch exchange and to the application processor.
When an agent performs a log-in operation on the terminating call dedicated line of the extension telephone set, a terminating call for the group to which the extension telephone set belongs is transferred to the terminating call dedicated line of the extension telephone set in accordance with a predetermined terminating distributing algorithm. When the extension telephone set responds to the terminating call, call data on the contents of the procedure (response time, talk end time, etc.,) is reported together with the logical number of the terminating call dedicated line and the agents ID number to the application processor and is stored therein for each of the agents, extension telephone groups, and terminating call dedicated lines.
While the same terminating call dedicated line (extension telephone set) can be used by different agents so as to enable shift operation, call data is stored for each of the agents' ID numbers, so that there are no problems in the management of a quantity of work of each agent. However, unless both of the terminating call dedicated line and the agent belong to the same extension telephone group, a log-in operation is impossible. Namely, even if an agent belonging to a predetermined extension telephone set group tries to perform a log-in operation on the terminating call dedicated line of a different extension telephone set group, the log-in operation will become ineffective. This is because call data would go out of control if the same agent is permitted to perform a log-in operation on a plurality of different extension telephone set groups since call data is managed for each of the agents, extension telephone set groups and terminating call dedicated lines.
The supervisor can change the setting of the terminating call dedicated terminal by operating a data setting terminal (for example, teletypewriter) annexed to the private branch exchange. For example, when an extension telephone set group receives a large number of terminating calls, the agent can allocate new extension telephone sets for use as terminating call dedicated telephone sets to the extension telephone set group. When an extension telephone set group receives a small number of terminating calls, the agent can reduce the number of extension telephone sets in the extension telephone set group. Thus, the terminating call processing can be performed appropriately for every group of extension telephone sets. In conventional telephone systems, a problem arises, however, if the number of the terminating calls to be processed in one extension telephone set group temporarily increases rapidly so that the extension telephone sets belonging to that group cannot handle all of these terminating calls. To cope with such situations, it is required to operate a teletypewriter provide at a remotely located private branch exchange. Thus, the conventional telephone systems have a problem in speedy handling of such situations.